Dear friends,

My moodle version 3.5.2

webserver nginx

The blue button of "Enrol me" was at the bottom of the course, every time participant press on that button, then the website will run a little bit, then halt for a very long time, and finally and waiting for so long until it appear this message

504 Gateway Time-out

When I refresh (reload) the page, then the enrolment was succeed. Even though it was successfully enrolled, but still there was error gateway time out. 

I have tried unenrolled and enrol again, still the same problem.

Thank you very much.
Nyanabhadra